'Foolish' in the Bible

This is what the Lord has said: A curse on the foolish prophets who go after the spirit which is in them and have seen nothing!

For this cause you will see no more foolish visions or make false use of secret arts: and I will make my people free from your power; and you will be certain that I am the Lord.

Now when she saw that her hope was made foolish and gone, she took another of her little ones and made him into a young lion.

And her prophets have been using whitewash, seeing foolish visions and making false use of secret arts, saying, This is what the Lord has said, when the Lord has said nothing.